Fire resisting insulating material and building construction embodying the same



March 12, 1957 E. L. HOLTSFORD 2,785,099

FIRE RESISTING INSULATING MATERIAL AND BUILDING CONSTRUCTION EMBODYINGTHE SAME Filed Sept. 5. 1950 2 She'ets-Sheet l INVENTOR. ff K657 1., H01IZSFOKO March 1957 E. L. HOLTSFORD 2 785,099

FIRE RESISTING INSULATING MATERIAL. AND BUILDING Filed Sept. 5. 1950CONSTRUCTION EMBODYING THE SAME 2 Sheets-Sheet 2 rawzmwee "Fazxiussanumau.

TIME vm/ #0065 INVENTOR. ERA/57 L. l/OIJSFORD United States Patent FIRERESISTING INSULATING MATERIAL AND BUILDING CONSTRUCTION EMBODYING THESAME Ernest L. Holtsford, Birmingham, Ala., assignor to BadhamInsulation Company, a corporation of Alabama Application September 5,1950, Serial No. 183,266

2 Claims. (Cl. 154-44) My present invention relates to fire resistantinsulating materials and building construction embodying the same, andmore particularly to a material and construction which shall form asound absorbing, fire resistant ceiling construction.

An object of my invention is to provide fire resistant wall or ceilingconstruction making use of bats or layers of non-inflammable fibrousmaterial such as mineral wool, rock wool, or similar materials made ofglass and the like, in combination with metallic foil so associated withthe non-inflammable material as to make it more etfective in protectingthe part of the building behind the wall or above the ceiling, and aconstruction which shall be effective to hold the temperature of part ofthe building behind or above the same below the maximum temperaturespermitted by prescribed fire regulations.

A more specific object is to provide ceiling construction which shall befire resistant as well as sound deadening, such construction embodyingthe usual fire resistant acoustical tile below and my improved fireresistant insulating material above.

Another object is to provide a combined fire resisting and acousticalceiling in which the degree of fire resistance is increased by theprovision of a sheet ofthin metal foil, preferably aluminum, spread ontop of the acoustical tile with a layer of the wool-like insulatingmaterial on top of the sheet. Alternately, I may place the sheet of foilintermediate the upper and lower surfaces of the upper layer of fibrousmaterial.

Another object is to provide a bat of non-inflammable fibrous materialhaving secured either to the underside thereof or intermediate thethickness thereof a sheet of metal foil, thereby to decrease thetransfer of heat through the bat.

A further object is to provide a bat of heat insulating materialcomprising a bat proper of non-inflammable mineral wool-like materialhaving glued or otherwise secured to its under surface a sheet of metalfoil which projects past one or more sides of the bat as the bat isviewed in plan, whereby when such bats are laid side by side theprojecting lengths of foil bridge or cover the crack therebetween,adding to the fire resistance of the ceiling or wall in which such batsare placed.

Briefly, I have found that I can construct an acoustical ceiling whichmeets accepted fire tests by placing above the usual acoustical tile orthe like an improved form of fire resisting material. This materialconsists essentially of low density bats or layers of non-inflammablefibers in combination with a thin sheet of metal foil. The physicalrelationship between the foil and the insulating material may takevarious forms. First, the metal foil may be laid directly on top of theacoustical tile and the non-inflammable material spread in loose formthereover.

Secondly, the foil sheets may be secured by a suitable adhesive or glueto the underside of a bat of the material, and the bat then laid withthe foil sheet down, directly on top of the acoustical tile. Thirdly,the sheet of metal foil may be glued into the bat of material,intermediate its thickness, preferably nearer the bottom side than theupper side.

When a ceiling construction embodying my invention is subjected to astandard fire test, for instance the one prescribed by The AmericanSociety for Testing Materials, I find that it fully meets therequirements of such test. It appears that the sheet of foil not onlyspreads localized heat evenly throughout the hat or layer of material,but that if subjected to the temperature at which the foil oxidizes itbinds the fibers of the bat together, preventing the bat from eroding.Thus, I have discovered that even when sections of the acoustical tileare eroded away due to high temperatures and/or flame action, the foiloxidizes and binds with the adjacent fibers of the bat or layer,resulting in lowering considerably the erosion effect of the heat andflame playing on the bat itself. Over such an area, therefore, myimproved construction is highly effective in preventing the throughpassage of flame, thus protecting parts of the building above theceiling.

My invention is illustrated in the accompanying drawings forming a partof this application in which:

Fig. 1 is a fragmental perspective view with certain parts in sectionand showing my invention associated with a ceiling having a lower layerof acoustical tile and suspended in one of the usual ways;

Fig. 2 is a sectional view taken generally along line II-II of Fig. 1;

Fig. 3 is a perspective view of the form of the improved fire resistantbat shown in Figs. 1 and 2, partly broken away and in section;

Fig. 4 is a graph illustrating the results of a test run on a ceilingsection embodying the type of bat shown in Figs. 1, 2 and 3;

Fig. 5 is a plan view of a modified form of bat in which the sheet offoil material is secured to the bottom thereof; and,

Fig. 6 is a detail sectional view taken generally along line VIVI ofFig. 5.

Referring now to the drawings for a better understanding of my inventionand more particularly to Figs. 1 to 3 thereof, I illustrate a ceilingconstruction which is both noise reducing and fire resistant. I haveselected one form of suspension means for the acoustical tile, but itwill be understood that various means are now known, for suspending thesame from the superstructure above a ceiling. As shown, I illustrate aplurality of acoustical tile 10 which are grooved along their edges asat 11 in the customary manner. These tile usually are made ofnon-inflammable material such as rock-Wool, asbestos ol the like, andthe lower surfaces thereof may be provided with a plurality of holes 12.The holes 12 extend partway through the tile, and the materialsurrounding the holes is of relatively low density. The material formingthe tile 10 above the holes, while being of the same type of material asthe material surrounding the holes, is relatively denser.

Fitting in the adjacent edgewise openings of the tile 10 are T-shapedrunners 13. The runners 13 may be suspended from brackets 14 having anupper portion fitting over a small channel 16. The channels 16 areprovided at intervals in the construction and are in turn supported bylarger channels 17, fewer in number than the charm nels 16. The channels17 may be supported in any suitable manner from the building-structureabove'the ceiling, as for instance by means of the wires indicated at18. Suflice it to say here that the tile may be suspended from the upperpart of the building in any suitable way.

My invention consists in increasing the fire resisting qualities of sucha ceiling construction by the provision of an improved form of fireresisting bat of material indicated generally by the numeral 191. Asshown in Figs. 1, 2 and 3 the bat '19 maybe formed of fibrous materialsuch as rock-wool, mineral wool, lead wool, glass wool and any of theother and well known suitable forms of material similar thereto withrespect to density and flammability. The density of such materialsvaries-from about 2 /2 pounds per cubic foot to about 7' pounds percubic foot. Preferably, the bat 19. may be of the usual x 27 inch sizeand 2 to 4 inches thick.

Approximately /2 inch up into the bat from the surface thereof adjacentthe upper surface of. the tile 10 I secure in the hat a sheet of metalfoil indicated. by the numeral 21. The foil preferably is dead softaluminum on the order of .0007 to .0009 inch in thickness or a materialhaving substantially the heat transfer characteristics of aluminum. Inmaking the bat 191 may coat the upper and lower surfaces of the foil 21with a suitable adhesive such for instance as an inorganic binder oradhesive like the water base silicates with refractory fillers ofsuchnature as to be capable of withstanding temperature on the order of 2000F. A specific example of such material is sodium silicate with amagnesium oxide filler.

In constructing a wall embodying the type of bat shown in Figs. 1, 2 and3, the runners 13 and the upper framework for supporting theceilingisput up in the ordinary manner. As the tile 10 is put in placemy improved bats may be laid directly on the tile, between the runnersand beneath the channels 16. The bats 19 may be laid either as theceiling is being constructed or they may be put in place after theceiling is completely constructed.

At all events, they are placed so that they abut'along.

the sides and ends as closely as possible so as to leave as small acrack as possible therebetwecn.

In Fig. 4 I indicate the results of an actual test on a ceilingembodying the form of my invention shown in Figs. 1, 2 and 3. The curve22 represents a standard temperature curve plotted against time andtemperature for the test of a 2 inch mineral wool bat placed above inchthick non-combustible acoustical tile, The dotdash line 23 representsthe maximum allowable backing temperature, namely the temperature on topof the but 19 or on the bottom of the buildingstructure above the bats.Curve 24 represents the actual test, run under standard conditions, ofmy improved bat in the form shown in Figs. 1, 2 and 3 when placed QVI%inch noncombustible acoustical tile. It will be seen that the curve 24shows that the resistance to heat transmission of my improved ceilingconstruction is entirely adequate, and that it falls well below themaximum allowable for the times shown. In the type of bat represented bythe curve 24, the material used was rock-wool having a density of 6 to 7pounds per cubic foot. The foil was placed /2 inch from the bottom ofthe bat and consisted of a sheet of dead soft aluminum on the order of.0007' to .0009 inch in thickness.

Upon continuing to subject the ceiling construction shown by test curve24 to increased temperatures, 1 found that eventually the acousticaltile 10 eroded away, exposing the lower surface of the bat 19. After aperiod of time the lower part of the bat 19 beneath the sheet 21 alsoeroded away. This permitted the sheet 21 to oxidize at the point wherethe flame was directly applied and in oxidizing the aluminum bonded tothe fibers of the upper part of the bat adjacent thereto. The effect ofthis was to materially decrease furthererodingefiect on the fibrousmateriaLeven though the flame continued to play on the same area. Thecombination of the oxidized aluminum and the fibers of the bat'wassutficient to bridge over the hole eroded away through the tile andlower part of the bat and to prevent the upper part of the bat 19 fromfalling therethrough.

In some instances I may prefer to place the strip or sheet 21a beneaththe lower surface of the bats of material 19a indicated in Figs. 5; and6. Also, in order to have sufficient of the foil material to assure thatany cracks left between adjacent bats 19:: are covered I may permit thefoil sheet to overhang the long sides of the bat as indicated at 26,thus to provide flaps. In placing the bats 19a I so lay them that theflaps 26 overlie one another, further excluding the penetration of flamethrough the ceiling structure. If desired, the sheet 21a may beadhesively secured to the lower surface of the bat 19a with one of theadhesives previously mentioned.

From the foregoing it will be apparent that I have devised an improvedfire resisting material and an improved ceiling construction embodyingthe same. In actual practice I have found that my invention isparticularly effective in equalizing the heat from a hot spot or hotarea throughout the bat containing the foil sheet. Further, due to theshiny'surface of such foil material it is particularly effective inreflecting radiant heat, further lowering the temperature above thebats. My invention is economical and practical in every respect. Thefoil 21 or 21a may conveniently be of the type currently sold forhousehold purposes, and hence is very inexpensive. The oxidizingtemperature ofsuch aluminum is around 1300 F. to 2000 F. 'Its effectin'combination with the'ceiling structure shown in reflecting heatdownwardly, in equalizing heat throughout the bat, and in combining whenoxidized with the fibers of the bat adjacent thereto, all add togetherto make my improved construction far superior to any fire resistantceiling with which I am familiar. In the appended claims the term wallis intended to include a ceiling.

While I have shown my invention in but two forms,

it will be obvious to those skilled in the art that it is not solimited, but is susceptible of various other changes and modificationswithout departing from the spirit thereof, and I desire, therefore thatonly such limitations shall be placed'thereupon as are specifically setforth in the appended claims.

What I claim is:

1. In fire resistant ceiling construction, a lower layer of acousticaltile formed of fire resistant material, means supporting the tile alongthe edges thereof, a layer of mineral Wool in the form of unwoven randomarranged fibers substantially covering the upper surface of the tileandplaced with its lower surface lying directly on the tile, said layerof mineral wool being from two to four inchcs thick and having a densityof between two and five-tenths to seven pounds per cubic foot, and animperforate sheet of aluminum foil co-extensive in area with the area ofthe mineral wool layer located intermediate theupper and lower surfacesof said layer of mineral wool and lying substantially parallel to theupper surface of the layer of tile.

2. in tire resistant ceiling construction, a lower layer of acousticaltile formed of fire resistant material, means supporting the tile inspaced relation to a superjacent part of the building, a layercomprising mineral wool bats of unwoven random arranged fibers, saidbats lying side by side in contact with each other directly on the uppersurface of the tile layer and substantially covering the upper surfaceof the tile layer, saidbats being from two to four inches thick andhaving a density of from two and five-tenths to seven pounds per cubicfoot, and an imperforate sheet of aluminum foil on the order of nine-tenthousandths inch thick in each'bat between the upper and lower surfacesthereof and lying substantially parallel to v the upper surface of saidtile layer, said sheets of foil 5 being substantially co-extensive inarea with the area of the bats.

References Cited in the file of this patent UNITED STATES PATENTS 5449,152 Enricht Mar. 31, 1891 1,914,345 Roos June 13, 1933 1,926,679Kellogg et a1. Sept. 12, 1933 1,994,439 S1ide1 Mar. 12, 1935 w 6Stranahan Oct. 13, 1936 Ross et a1. Apr. 20, 1937 Johnson Sept. 5, 1939Parkinson Oct. 24, 1939 Wasserman Nov. 19, 1940 Slayter Oct. 7, 1947Tucker July 24, 1951 FOREIGN PATENTS Switzerland Jan. 16, 1940

1. IN FIRE RESISTANT CEILING CONSTRUCTION, A LOWER LAYER OF ACOUSTICALTILE FORMED OF FIRE RESISTANT MATERIAL, MEANS SUPPORTING THE TILE ALONGTHE EDGES THEREOF, A LAYER OF MINERAL WOOL IN THE FORM OF UNWOVEN RANDOMARRANGED FIBERS SUBSTANTIALLY COVERING THE UPPER SURFACE OF THE TILE ANDPLACED WITH ITS LOWER SURFACE LYING DIRECTLY ON THE TILE, SAID LAYER OFMINERAL WOOL BEING FROM TWO TO FOUR INCHES THICK AND HAVING A DENSITY OFBETWEEN TWO AND